EP 0 215 220 teaches a three-point seat belt configuration in which a shoulder belt part is placed through a guide slot having an approximately S-shaped curve.
EP 0 254 260 A1 teaches a webbing guide for use with a seat belt apparatus, the webbing guide having a guide hole for the shoulder webbing portion. The webbing guide has crank-shaped outline to keep the shoulder webbing from becoming twisted or reversed in the guide hole. The webbing guide additionally has an upwardly open slot, through which the shoulder belt part may be removed from the guide.
U.S. Pat. No. 5,350,196 teaches a clamping device for use with a restraining belt. The clamping device has a lever actuated cam, and in the clamped position the lever closes off an opening in the slot.
DE 198 38 930 C1 teaches a seat belt arrangement comprising a shoulder belt part which is placed through a slotted guide of a guide clip in the region of a backrest of the seat provided with a folding mechanism. The slotted guide is formed at least partially by an unlocking lever for unlocking the folding mechanism of the backrest and which, for unlocking, may be moved from the position closing the slot laterally in the transverse direction of the vehicle, the slot being opened up.